The present invention relates to a reservoir tank mounted to a master cylinder or a hydraulic booster of a vehicle brake system.
A typical conventional reservoir tank is shown in FIG. 13B, which includes a tank body 1 comprising a lower shell la and an upper shell 1b, which are joined together by melting their mating surfaces with a hot plate H (FIG. 13A), putting the top shell 1b onto the lower shell 1a so that their molten mating surfaces contact each other, and allowing the mating surfaces to harden so as to be fixed to each other.
The reservoir tank includes partition walls 2 that divide the interior of the tank body 1 into a plurality of chambers, thereby minimizing pulsation of hydraulic fluid F, a filter 4 provided in one of the chambers through which hydraulic fluid F flows into and out of the reservoir tank, and a float 5 and a fluid level sensor 6 provided in a fluid level detecting chamber 3. The flow of hydraulic fluid F into and out of the fluid level detecting chamber 3 is restricted by a partition plate 7. The upper shell 1b has a hydraulic fluid supply port 8. (This particular type of reservoir tank is disclosed in JP patent publication 11-20660.)
The fluid level sensor 6 has a shaft 6a which carries at its top end a retainer 9 that restricts the movement of the float 5 and also prevents separation of the float 5 from the fluid level sensor 6. The retainer 9 is e.g. a snap ring fixed to the shaft of the sensor 6 by caulking or bonding.
Typically, different kinds of reservoir tanks are used in different types of motor vehicles manufactured not only by different car manufacturers but by a common car manufacturer. To reduce costs, it is desired that such different kinds of reservoirs be manufactured using as many common parts as possible.
An object of the present invention is therefore to provide a reservoir tank of which a greater number of parts can also be used for different kinds of reservoir tanks.